| Wheat is one of the most important cereal crops in China. The continuously steady increase of wheat production was demand along with the increasing of mankind population. However, the increase of wheat production depends on increasing yield per unit area, improvement wheat plant type has an important role to improve the yield. Leaves as the main photosynthetic organs of wheat, is one of the important morphological indicators in high-yielding breeding. Moderate leaf rolling can make leaves blades upright and decrease drooping, improve light condition and reduce the extinction coefficient of wheat group, thereby higher photosynthetic efficiency lays a foundation for high yield. Therefore, study roll leaf of wheat, not only contribute to the understanding of roll leaf development mechanisms, but also help us to promote crop’s output and quality through improved its genetic character.The plant with roll flag leaf derived from the progenies of common wheat CM 107 and Th. intermedium. The plant exhibits similar agronomic traits to ChuanMai107, and is immune to powdery mildew and stripe rust in field. In this study, the plant with roll leaf was studied by ISH (in situ hybridization), Sequential C-banding-GISH and Frozen section techniques. The main results are as follows:1. The plant with roll leaf base of the flag leaf was obviously roll, but its progenies has segregation into roll and normal leaf plant, all these plants are immune to powdery mildew and stripe rust in field, and exhibit similar agronomic traits to ChuanMai107.The Fi population’s of plant with roll leaf and ChuanMai107 and line 723 respectively, show that segregation of plants with roll and normal leaf, which was close to the proportion of 1:1, the F1 population’s of plant with roll leaf and line 07-2 and MY26 show normal leaf plants.2. The somatic chromosome number per cell of plant with roll leaf was 2n=41, meiotic metaphase I of pollen mother cells (PMCs) was 2n=20 Ⅱ+Ⅰ, and suggesting it was lost one chromosome. The somatic chromosome number per cell of plant with normal leaf was 2n=42 with 2n=21 Ⅱ at meiotic metaphase Ⅰ of pollen mother cells (PMCs).3. The GISH (Genomic in situ hybridization) with Th. intermedium and Pseu. Strigosa genomic DNA respectively as probes of plant with roll and normal leaf displayed that a St genome chromosomal fragment of Th. intermedium was found to be transferred into one pair short arms of wheat chromosome with a interstitial translocation.4. Double-FISH (Double fluorescence in situ hybridization) with pAs1 and pSc 119.2 show that the plants with roll leaf missing one 4D chromosome. The chromosome translocations occurred in plants with roll and normal leaf are located on chromosome A genome.5. The sequential GISH-FISH of plants with roll and normal leaf first with Th. intermedium genomic DNA as probes, China Spring genomic DNA as block, then Double-FISH with pTa-535 and Triticum urartu genomic DNA as probes, the mixed Aegilops speltoides and Aegilops tauschii genomic DNAs as blocks, and sequential Giemsa C-banding and GISH analyses were carried out. These results revealed that the translocation occurred in the wheat chromosome 6AS, the length of translocation fragment was about four-fifths of the entire short arm.6. By the method of frozen section, we found that bulliform cells of the plants with roll leaf were smaller volume, more shrinkage and more numbers than ChuanMai 107.7. based on aboved results, it could concluded that the rolling leaf was caused by interaction between miss of one 4D chromosome and wheat genetic background. |
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